1. Field of the Invention
The invention relates in general to a pixel structure of a display apparatus, and more particularly to a pixel structure with a storage capacitor formed by coupling two metal plates.
2. Description of the Related Art
FIG. 1A illustrates part of a conventional pixel structure in a display panel. A pixel 100 is controlled by a scan line SC1 and receives a data signal transmitted from a data line DT1. FIG. 1B is a cross-sectional view of the pixel 100 in FIG. 1A taken along a line A1-B1-C1.
As shown in FIG. 1B, a pixel structure of the pixel 100 includes an indium tin oxide (ITO) layer, a passivation layer, two metal plates, an interlayer dielectric (ILD) layer, an oxide layer and a polysilicon layer. The pixel 100 includes a transistor 110 and storage capacitors Cp1 and Cp2. A gate of the transistor 110 is formed by a polysilicon area 160 to receive a signal of the scan line SC1. A drain of the transistor 110 is connected to a metal plate 130b. The metal plate 130b receives a data signal of the data line DT1. A source of the transistor 110 is formed by a doped polysilicon layer 150 and connected to a metal plate 130a. The metal plate 130a is connected to the ITO layer 120. A metal plate 140 is located between the metal plate 130a and the doped polysilicon layer 150 for receiving common voltage Vcom1.
The voltage of the metal plate 130a is the same as the voltage of the doped polysilicon layer 150. The storage capacitor Cp1 is formed by the metal plate 130a and the metal plate 140. The storage capacitor Cp2 is formed by the metal plate 140 and the doped polysilicon layer 150. When the scan line SC1 is enabled, pixel voltage related to the data signal of the data line DT1 is stored in the storage capacitors Cp1 and Cp2.
However, because metal particles often remain between the metal plates 130a and 140 due to manufacturing problems, a short circuit occurs between the metals 130a and 140 accidentally. As a result, the storage capacitor Cp1 between the metal plates 130a and 140 disappears, which causes a bright spot in the pixel 100.